The car will drive but I am not able to place it in park or reverse, just neutral and of course drive. Any advice would be helpful.

It was the shift cable assembly (both inner and outer) and it has to be replaced. Any idea on a ballpark figure on the cost for it?

Try calling Folger Automotive in Charlotte, they still stock Isuzu parts or can special order them. Just ask for parts dept: (704) 536-9635